0277 - Coworth Spa

Surrey

Situated in 240 acres of protected woodland, this eco-luxury spa forms part of a new Dorchester Hotel development. The structure is partially buried, minimising the impact on its environment, with banked landscaping running onto a green roof. It is the world’s first spa to be built from carbon negative lime hemp walling, which is combined with above-ground traditional timber studwork and natural finishes.

The super structure is typically glulam timber-framed, with columns supporting cross-laminated roof panels. It was designed, procured and constructed within eight months, of which the timber frame elements were completed within six weeks.

HTS completed several studies to determine the carbon impact of various solutions. A new remote energy centre includes a biomass boiler, fuelled by willow harvested on the estate, and ground water heat-transfer system that meet 50% of the spa’s energy demands. The largest horizontal ground source cooling system in Europe has been installed, achieving a carbon reduction of 41% compared to an air-cooled system. The elegantly executed monocoque structure reduced the excavation depth by 0.5m and features a luxury underground pool.